The present invention relates generally to tiller apparatus, and more particularly to novel and improved automatic retractable tillers adapted for tilling interstitial unplanted soil between plants or objects in a row and method of guiding same.
Cultivating or tilling the interstitial unplanted soil between plants in a row to control weed growth, mulch, and aerate the soil is desirable to optimum plant growth and good husbandry. There have been a number of prior developments and inventions relating to tillers adapted to till the interstitial soil between plants in a row, including several embodiments of such devices invented by one or more of the joint inventors of this invention. For example, U.S. Pat. No. 4,287,955 issued to Jack F. Anderson discloses such an in-row rotary tiller device adapted for mounting on a skid turn vehicle. Also, the co-pending patent application Ser. No. 240,137, entitled Retractable In-Row Tiller Device, filed Mar. 2, 1981, and co-pending patent application Ser. No. 355,100, entitled Method and Apparatus for Guiding Retractable In-Row Tiller Device, filed Mar. 3, 1982, both of which were invented by Jack F. Anderson and Clayton Melrose, disclose automatic retractable in-row tillers for mounting on a vehicle and tilling between plants in a row.
The following patents disclose some other examples of devices which include some mechanism for moving tiller apparatus laterally in relation to the tractor into and out of the area between plants in a row: U.S. Pat. Nos. 2,489,633 issued to Fulgham; 2,664,802 issued to I. Myer; 2,718,836 issued to E. P. Pertics, et al; 2,764,077 issued to E. P. Pertics, et al; 3,059,704 issued to Kasatkin; 3,117,632 issued to V. G. Caggiano, Jr.; 3,138,208 issued to S. G. Simms; 3,190,364 issued to Maloney; 3,200,890 issued to Courtway; and 3,913,681 issued to W. D. Lincoln, et al. These prior art devices typically include cumbersome mechanical controls for extending and retracting a tiller into and out of the row. The U.S. Pat. Nos. 2,489,633 issued to Fulgham, 3,138,208 issued to Simms, and 3,200,390 issued to Courtway are examples of such devices that utilize various mechanical apparatus for extending and retracting a tiller into and out of a row. The Myer patent, U.S. Pat. No. 2,644,802, utilizes an electric solenoid mechanism for extending and retracting a tiller into and out of row. The U.S. Pat. Nos. 2,718,836 issued to Pertics, et al, 2,764,077 issued to Pertics, et al, 3,059,704 issued to Kasatkin, 3,913,681 issued to Lincoln, et al, all include hydraulic controls. The apparatus of the mechanically and electrically controlled tiller devices are cumbersome, and even the prior art hydraulically controlled tillers usually lack effective, sensitive, response and speed of travel in retracting and extending into the row.
While some of the prior art devices, such as those disclosed in U.S. Pat. Nos. 2,489,633 issued to Fulgham, 2,664,802 issued to Myer, 3,117,632 issued to Caggiano, 3,138,208 issued to Simms, 3,200,890 issued to Courtway, and 3,913,618 issued to Lincoln, et al include sensing apparatus for sensing the plants and causing the tiller apparatus to move around the plants, such devices are lacking in specific desirable features such as accurate response to objects sensed, effective speed of response in retracting and extending a tiller out of and into the row, adaptability to varying soil conditions and terrain, and sufficient convenient manual control options to allow the operator flexibility in dealing with various sized weeds and other objects that might be encountered in the row in addition to the plants to be cultivated.
In addition to the prior art mentioned above, the U.S. Pat. No. 1,145,240, issued to Gould and U.S. Pat. No. 2,990,890, issued to Butterfield disclose retractable rotary tillers equipped with mechanical retraction devices. U.S. Pat. No. 1,664,789, issued to von Meyenburg U.S. Pat. No. 2,651,246, issued to Perters, et al, U.S. Pat. No. 3,169,583, issued to Thurow, U.S. Pat. No. 3,419,086, issued to Giusti, et al, and U.S. Pat. No. 4,044,839, issued to van der Lely, all disclose various structures for non-retractable rotary tillers. In addition to the tiller patents mentioned above, there are a number of mower and saw devices which have been adapted for mounting on vehicles and include some form of retraction and extension apparatus for moving the mowers or saws towards and away from the vehicle. Such retractable mower or saw devices are shown in U.S. Pat. No. 2,719,081, issued to Allen, et al, U.S. Pat. No. 2,662,561, issued to Duncan, U.S. Pat. No. 2,699,635, issued to Burton, U.S. Pat. No. 2,601,366, issued to Chapman, U.S. Pat. No. 3,003,299, issued to Smith, et al, U.S. Pat. No. 3,061,996, issued to Ripps, U.S. Pat. No. 3,274,762, issued to Jolls, U.S. Pat. No. 4,048,789, issued to Cartner, U.S. Pat. No. 2,997,835, issued to Stewart, U.S. Pat. No. 2,840,974, issued to Dunn, et al, and U.S. Pat. No. 4,206,580, issued to Truax, et al. The mower of saw patents issued to Allen, Duncan, Burton, Chapman, and Smith are equipped with mechical retraction devices, and the movers shown in the patents issued to Ripps, Jolls, Cartner, Stewart, Dunn, and Truax are equipped with hydraulic retraction mechanisms.
In spite of the advancements in the art made by those prior art inventions mentioned above, including those invented by one or more of the co-inventors of this invention, it has been found that additional improvements in structural and control features are desirable for improving reliability, sensitivity, and responsiveness for a wider variety of applications in diverse soil conditions and applications. For example, light and sandy soils, hard and heavy soils, and bermed or sharply contoured areas present unique control problems not adequately met by prior art devices. Also, it has been found to be desirable to include control features and inherent functional weaknesses in the automatically controlled equipment. Further, it has been found that substantial improvements can still be made in operator control convenience.